Hello and welcome to the site. Thank you for your question.
You have a few questions that need an answer
My home address is registered as the company address, and the roof has recently started leaking. Is it acceptable to claim building repair and work as a company expense
You can not claim this repair charge as a business expense as the property is primarily your private residence albeit the address acts as the company's registered office address. If the property were soley for business use then the costs would be allowable.
can I pay myself the lump sum as a dividend (with no salary), and how do I make sure I'm paying the right amount of tax? So sorry for the lack of basic understanding!
Yes you can pay your self a lump sum as dividend. Please bear in mind, you can only pay dividend out of taxed profits... If your only income is £5,000 and say after expenses the profit turns out to be £4,500. Then corporation tax would be £900 and you would have £3,600 available for distribution as dividends.
Dividends carry a notional tax charge of 10%. If your total income in a tax year remains at basic rate levels (£41,865 for 2014-15) then there is no further tax to be paid on dividends received.
If you are operating as LTD company then you should not be paying Class 2 NI as this is payable by self employed.
I hope this is helpful and answers your question.
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